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NAME

       quotactl - manipulate disk quotas

SYNOPSIS

       #include <sys/quota.h>
       #include <xfs/xqm.h> /* for XFS quotas */

       int quotactl(int cmd, const char *special, int id, caddr_t addr);

DESCRIPTION

       The  quota  system  can  be used to set per-user, per-group, and per-project limits on the
       amount of disk space used on a filesystem.  For each user and/or group, a soft limit and a
       hard  limit  can  be set for each filesystem.  The hard limit can't be exceeded.  The soft
       limit can be exceeded, but warnings will ensue.  Moreover, the user can't exceed the  soft
       limit for more than grace period duration (one week by default) at a time; after this, the
       soft limit counts as a hard limit.

       The quotactl() call manipulates disk quotas.  The cmd argument indicates a command  to  be
       applied  to the user or group ID specified in id.  To initialize the cmd argument, use the
       QCMD(subcmd, type) macro.  The type value is either USRQUOTA, for user  quotas,  GRPQUOTA,
       for  group quotas, or (since Linux 4.1) PRJQUOTA, for project quotas.  The subcmd value is
       described below.

       The special argument is a pointer to a null-terminated string containing the  pathname  of
       the (mounted) block special device for the filesystem being manipulated.

       The  addr argument is the address of an optional, command-specific, data structure that is
       copied in or out of the system.  The interpretation of addr is given with  each  operation
       below.

       The subcmd value is one of the following operations:

       Q_QUOTAON
              Turn  on  quotas for a filesystem.  The id argument is the identification number of
              the quota format to be used.  Currently, there are three supported quota formats:

              QFMT_VFS_OLD The original quota format.

              QFMT_VFS_V0  The standard VFS v0 quota format, which can  handle  32-bit  UIDs  and
                           GIDs and quota limits up to 2^42 bytes and 2^32 inodes.

              QFMT_VFS_V1  A  quota  format that can handle 32-bit UIDs and GIDs and quota limits
                           of 2^64 bytes and 2^64 inodes.

              The addr argument points to the pathname of a file containing the  quotas  for  the
              filesystem.    The  quota  file  must  exist;  it  is  normally  created  with  the
              quotacheck(8) program

              Quota information can be also stored in hidden system inodes  for  ext4,  XFS,  and
              other  filesystems  if the filesystem is configured so.  In this case, there are no
              visible quota files and there is no need to use quotacheck(8).   Quota  information
              is always kept consistent by the filesystem and the Q_QUOTAON operation serves only
              to enable enforcement of quota limits.  The presence of hidden system  inodes  with
              quota  information  is  indicated  by  the DQF_SYS_FILE flag in the dqi_flags field
              returned by the Q_GETINFO operation.

              This operation requires privilege (CAP_SYS_ADMIN).

       Q_QUOTAOFF
              Turn off quotas for a filesystem.  The addr and id  arguments  are  ignored.   This
              operation requires privilege (CAP_SYS_ADMIN).

       Q_GETQUOTA
              Get disk quota limits and current usage for user or group id.  The addr argument is
              a pointer to a dqblk structure defined in <sys/quota.h> as follows:

                  /* uint64_t is an unsigned 64-bit integer;
                     uint32_t is an unsigned 32-bit integer */

                  struct dqblk {      /* Definition since Linux 2.4.22 */
                      uint64_t dqb_bhardlimit;  /* Absolute limit on disk
                                                   quota blocks alloc */
                      uint64_t dqb_bsoftlimit;  /* Preferred limit on
                                                   disk quota blocks */
                      uint64_t dqb_curspace;    /* Current occupied space
                                                   (in bytes) */
                      uint64_t dqb_ihardlimit;  /* Maximum number of
                                                   allocated inodes */
                      uint64_t dqb_isoftlimit;  /* Preferred inode limit */
                      uint64_t dqb_curinodes;   /* Current number of
                                                   allocated inodes */
                      uint64_t dqb_btime;       /* Time limit for excessive
                                                   disk use */
                      uint64_t dqb_itime;       /* Time limit for excessive
                                                   files */
                      uint32_t dqb_valid;       /* Bit mask of QIF_*
                                                   constants */
                  };

                  /* Flags in dqb_valid that indicate which fields in
                     dqblk structure are valid. */

                  #define QIF_BLIMITS   1
                  #define QIF_SPACE     2
                  #define QIF_ILIMITS   4
                  #define QIF_INODES    8
                  #define QIF_BTIME     16
                  #define QIF_ITIME     32
                  #define QIF_LIMITS    (QIF_BLIMITS | QIF_ILIMITS)
                  #define QIF_USAGE     (QIF_SPACE | QIF_INODES)
                  #define QIF_TIMES     (QIF_BTIME | QIF_ITIME)
                  #define QIF_ALL       (QIF_LIMITS | QIF_USAGE | QIF_TIMES)

              The dqb_valid field is a bit mask that is set to indicate the entries in the  dqblk
              structure  that are valid.  Currently, the kernel fills in all entries of the dqblk
              structure and marks them as valid in the dqb_valid field.  Unprivileged  users  may
              retrieve  only their own quotas; a privileged user (CAP_SYS_ADMIN) can retrieve the
              quotas of any user.

       Q_GETNEXTQUOTA (since Linux 4.6)
              This operation is the same as Q_GETQUOTA, but it returns quota information for  the
              next ID greater than or equal to id that has a quota set.

              The addr argument is a pointer to a nextdqblk structure whose fields are as for the
              dqblk, except for the addition of a dqb_id field that is used to return the ID  for
              which quota information is being returned:

                  struct nextdqblk {
                      uint64_t dqb_bhardlimit;
                      uint64_t dqb_bsoftlimit;
                      uint64_t dqb_curspace;
                      uint64_t dqb_ihardlimit;
                      uint64_t dqb_isoftlimit;
                      uint64_t dqb_curinodes;
                      uint64_t dqb_btime;
                      uint64_t dqb_itime;
                      uint32_t dqb_valid;
                      uint32_t dqb_id;
                  };

       Q_SETQUOTA
              Set  quota  information for user or group id, using the information supplied in the
              dqblk structure pointed to by addr.  The dqb_valid field  of  the  dqblk  structure
              indicates  which  entries  in  the  structure  have  been  set by the caller.  This
              operation supersedes the Q_SETQLIM and Q_SETUSE operations in  the  previous  quota
              interfaces.  This operation requires privilege (CAP_SYS_ADMIN).

       Q_GETINFO (since Linux 2.4.22)
              Get  information (like grace times) about quotafile.  The addr argument should be a
              pointer to a dqinfo structure.  This  structure  is  defined  in  <sys/quota.h>  as
              follows:

                  /* uint64_t is an unsigned 64-bit integer;
                     uint32_t is an unsigned 32-bit integer */

                  struct dqinfo {         /* Defined since kernel 2.4.22 */
                      uint64_t dqi_bgrace;  /* Time before block soft limit
                                               becomes hard limit */
                      uint64_t dqi_igrace;  /* Time before inode soft limit
                                               becomes hard limit */
                      uint32_t dqi_flags;   /* Flags for quotafile
                                               (DQF_*) */
                      uint32_t dqi_valid;
                  };

                  /* Bits for dqi_flags */

                  /* Quota format QFMT_VFS_OLD */

                  #define DQF_ROOT_SQUASH (1 << 0) /* Root squash enabled */
                                /* Before Linux v4.0, this had been defined
                                   privately as V1_DQF_RSQUASH */

                  /* Quota format QFMT_VFS_V0 / QFMT_VFS_V1 */

                  #define DQF_SYS_FILE    (1 << 16)   /* Quota stored in
                                                         a system file */

                  /* Flags in dqi_valid that indicate which fields in
                     dqinfo structure are valid. */

                  #define IIF_BGRACE  1
                  #define IIF_IGRACE  2
                  #define IIF_FLAGS   4
                  #define IIF_ALL     (IIF_BGRACE | IIF_IGRACE | IIF_FLAGS)

              The  dqi_valid field in the dqinfo structure indicates the entries in the structure
              that are valid.  Currently, the kernel fills in all entries of the dqinfo structure
              and marks them all as valid in the dqi_valid field.  The id argument is ignored.

       Q_SETINFO (since Linux 2.4.22)
              Set information about quotafile.  The addr argument should be a pointer to a dqinfo
              structure.  The dqi_valid field of the dqinfo structure indicates  the  entries  in
              the  structure  that  have  been  set by the caller.  This operation supersedes the
              Q_SETGRACE and Q_SETFLAGS operations in the  previous  quota  interfaces.   The  id
              argument is ignored.  This operation requires privilege (CAP_SYS_ADMIN).

       Q_GETFMT (since Linux 2.4.22)
              Get  quota  format used on the specified filesystem.  The addr argument should be a
              pointer to a 4-byte buffer where the format number will be stored.

       Q_SYNC Update the on-disk copy of quota usages for a filesystem.  If special is NULL, then
              all  filesystems  with  active  quotas  are sync'ed.  The addr and id arguments are
              ignored.

       Q_GETSTATS (supported up to Linux 2.4.21)
              Get statistics and other generic information about the quota subsystem.   The  addr
              argument should be a pointer to a dqstats structure in which data should be stored.
              This structure is defined in <sys/quota.h>.   The  special  and  id  arguments  are
              ignored.

              This   operation   is   obsolete  and  was  removed  in  Linux  2.4.22.   Files  in
              /proc/sys/fs/quota/ carry the information instead.

       For XFS filesystems making use of the XFS Quota Manager (XQM), the  above  operations  are
       bypassed and the following operations are used:

       Q_XQUOTAON
              Turn  on  quotas  for  an  XFS filesystem.  XFS provides the ability to turn on/off
              quota limit enforcement with quota accounting.  Therefore, XFS expects addr to be a
              pointer  to  an  unsigned  int that contains a bitwise combination of the following
              flags (defined in <xfs/xqm.h>):

                  XFS_QUOTA_UDQ_ACCT  /* User quota accounting */
                  XFS_QUOTA_UDQ_ENFD  /* User quota limits enforcement */
                  XFS_QUOTA_GDQ_ACCT  /* Group quota accounting */
                  XFS_QUOTA_GDQ_ENFD  /* Group quota limits enforcement */
                  XFS_QUOTA_PDQ_ACCT  /* Project quota accounting */
                  XFS_QUOTA_PDQ_ENFD  /* Project quota limits enforcement */

              This operation requires privilege (CAP_SYS_ADMIN).  The id argument is ignored.

       Q_XQUOTAOFF
              Turn off quotas for an XFS filesystem.  As with Q_QUOTAON, XFS filesystems expect a
              pointer  to  an  unsigned  int that specifies whether quota accounting and/or limit
              enforcement need to  be  turned  off  (using  the  same  flags  as  for  Q_XQUOTAON
              operation).  This operation requires privilege (CAP_SYS_ADMIN).  The id argument is
              ignored.

       Q_XGETQUOTA
              Get disk quota limits and current usage for  user  id.   The  addr  argument  is  a
              pointer to an fs_disk_quota structure, which is defined in <xfs/xqm.h> as follows:

                  /* All the blk units are in BBs (Basic Blocks) of
                     512 bytes. */

                  #define FS_DQUOT_VERSION  1  /* fs_disk_quota.d_version */

                  #define XFS_USER_QUOTA    (1<<0)  /* User quota type */
                  #define XFS_PROJ_QUOTA    (1<<1)  /* Project quota type */
                  #define XFS_GROUP_QUOTA   (1<<2)  /* Group quota type */

                  struct fs_disk_quota {
                      int8_t   d_version;   /* Version of this structure */
                      int8_t   d_flags;     /* XFS_{USER,PROJ,GROUP}_QUOTA */
                      uint16_t d_fieldmask; /* Field specifier */
                      uint32_t d_id;        /* User, project, or group ID */
                      uint64_t d_blk_hardlimit; /* Absolute limit on
                                                   disk blocks */
                      uint64_t d_blk_softlimit; /* Preferred limit on
                                                   disk blocks */
                      uint64_t d_ino_hardlimit; /* Maximum # allocated
                                                   inodes */
                      uint64_t d_ino_softlimit; /* Preferred inode limit */
                      uint64_t d_bcount;    /* # disk blocks owned by
                                               the user */
                      uint64_t d_icount;    /* # inodes owned by the user */
                      int32_t  d_itimer;    /* Zero if within inode limits */
                                            /* If not, we refuse service */
                      int32_t  d_btimer;    /* Similar to above; for
                                               disk blocks */
                      uint16_t d_iwarns;    /* # warnings issued with
                                               respect to # of inodes */
                      uint16_t d_bwarns;    /* # warnings issued with
                                               respect to disk blocks */
                      int32_t  d_padding2;  /* Padding - for future use */
                      uint64_t d_rtb_hardlimit; /* Absolute limit on realtime
                                                   (RT) disk blocks */
                      uint64_t d_rtb_softlimit; /* Preferred limit on RT
                                                   disk blocks */
                      uint64_t d_rtbcount;  /* # realtime blocks owned */
                      int32_t  d_rtbtimer;  /* Similar to above; for RT
                                               disk blocks */
                      uint16_t d_rtbwarns;  /* # warnings issued with
                                               respect to RT disk blocks */
                      int16_t  d_padding3;  /* Padding - for future use */
                      char     d_padding4[8];   /* Yet more padding */
                  };

              Unprivileged   users  may  retrieve  only  their  own  quotas;  a  privileged  user
              (CAP_SYS_ADMIN) may retrieve the quotas of any user.

       Q_XGETNEXTQUOTA (since Linux 4.6)
              This operation is the same as Q_XGETQUOTA, but it  returns  (in  the  fs_disk_quota
              structure  pointed by addr) quota information for the next ID greater than or equal
              to id that has a quota set.  Note that since fs_disk_quota already has q_id  field,
              no   separate   structure   type   is  needed  (in  contrast  with  Q_GETQUOTA  and
              Q_GETNEXTQUOTA operations)

       Q_XSETQLIM
              Set disk quota limits  for  user  id.   The  addr  argument  is  a  pointer  to  an
              fs_disk_quota structure.  This operation requires privilege (CAP_SYS_ADMIN).

       Q_XGETQSTAT
              Returns  XFS  filesystem-specific  quota information in the fs_quota_stat structure
              pointed by addr.  This is useful for finding out how much space is  used  to  store
              quota  information,  and  also  to get the quota on/off status of a given local XFS
              filesystem.  The fs_quota_stat structure itself is defined as follows:

                  #define FS_QSTAT_VERSION 1  /* fs_quota_stat.qs_version */

                  struct fs_qfilestat {
                      uint64_t qfs_ino;       /* Inode number */
                      uint64_t qfs_nblks;     /* Number of BBs
                                                 512-byte-blocks */
                      uint32_t qfs_nextents;  /* Number of extents */
                  };

                  struct fs_quota_stat {
                      int8_t   qs_version; /* Version number for
                                              future changes */
                      uint16_t qs_flags; /* XFS_QUOTA_{U,P,G}DQ_{ACCT,ENFD} */
                      int8_t   qs_pad;   /* Unused */
                      struct fs_qfilestat qs_uquota;  /* User quota storage
                                                         information */
                      struct fs_qfilestat qs_gquota;  /* Group quota storage
                                                         information */
                      uint32_t qs_incoredqs;   /* Number of dquots in core */
                      int32_t  qs_btimelimit;  /* Limit for blocks timer */
                      int32_t  qs_itimelimit;  /* Limit for inodes timer */
                      int32_t  qs_rtbtimelimit;/* Limit for RT
                                                  blocks timer */
                      uint16_t qs_bwarnlimit;  /* Limit for # of warnings */
                      uint16_t qs_iwarnlimit;  /* Limit for # of warnings */
                  };

              The id argument is ignored.

       Q_XGETQSTATV
              Returns XFS filesystem-specific quota information in the fs_quota_statv pointed  to
              by  addr.   This  version  of the operation uses a structure with proper versioning
              support, along with appropriate layout  (all  fields  are  naturally  aligned)  and
              padding  to  avoiding  special compat handling; it also provides the ability to get
              statistics regarding the project quota file.  The fs_quota_statv  structure  itself
              is defined as follows:

                  #define FS_QSTATV_VERSION1 1 /* fs_quota_statv.qs_version */

                  struct fs_qfilestatv {
                      uint64_t qfs_ino;       /* Inode number */
                      uint64_t qfs_nblks;     /* Number of BBs
                                                 512-byte-blocks */
                      uint32_t qfs_nextents;  /* Number of extents */
                      uint32_t qfs_pad;       /* Pad for 8-byte alignment */
                  };

                  struct fs_quota_statv {
                      int8_t   qs_version;    /* Version for future
                                                 changes */
                      uint8_t  qs_pad1;       /* Pad for 16-bit alignment */
                      uint16_t qs_flags;      /* XFS_QUOTA_.* flags */
                      uint32_t qs_incoredqs;  /* Number of dquots incore */
                      struct fs_qfilestatv qs_uquota;  /* User quota
                                                          information */
                      struct fs_qfilestatv qs_gquota;  /* Group quota
                                                          information */
                      struct fs_qfilestatv qs_pquota;  /* Project quota
                                                          information */
                      int32_t  qs_btimelimit;   /* Limit for blocks timer */
                      int32_t  qs_itimelimit;   /* Limit for inodes timer */
                      int32_t  qs_rtbtimelimit; /* Limit for RT blocks
                                                   timer */
                      uint16_t qs_bwarnlimit;   /* Limit for # of warnings */
                      uint16_t qs_iwarnlimit;   /* Limit for # of warnings */
                      uint64_t qs_pad2[8];      /* For future proofing */
                  };

              The  qs_version  field  of  the  structure should be filled with the version of the
              structure supported by the callee (for now, only FS_QSTAT_VERSION1  is  supported).
              The  kernel  will  fill  the structure in accordance with version provided.  The id
              argument is ignored.

       Q_XQUOTARM  (since Linux 3.16)
              Free the disk space taken by disk quotas.  The addr argument should be a pointer to
              an  unsigned  int  value  containing  flags  (the  same  as  in  d_flags  field  of
              fs_disk_quota structure) which identify what types  of  quota  should  be  removed.
              (Note  that the quota type passed in the cmd argument is ignored, but should remain
              valid in order to pass preliminary quotactl syscall handler checks.)

              Quotas must have already been turned off.  The id argument is ignored.

       Q_XQUOTASYNC (since Linux 2.6.15; no-op since Linux 3.4)
              This operation was an XFS quota equivalent to Q_SYNC, but it is no-op  since  Linux
              3.4,  as  sync(1)  writes  quota  information to disk now (in addition to the other
              filesystem metadata that it writes out).  The special, id and  addr  arguments  are
              ignored.

RETURN VALUE

       On  success,  quotactl()  returns 0; on error -1 is returned, and errno is set to indicate
       the error.

ERRORS

       EACCES cmd is Q_QUOTAON, and the quota file pointed to  by  addr  exists,  but  is  not  a
              regular file or is not on the filesystem pointed to by special.

       EBUSY  cmd is Q_QUOTAON, but another Q_QUOTAON had already been performed.

       EFAULT addr or special is invalid.

       EINVAL cmd or type is invalid.

       EINVAL cmd is Q_QUOTAON, but the specified quota file is corrupted.

       EINVAL (since Linux 5.5)
              cmd is Q_XQUOTARM, but addr does not point to valid quota types.

       ENOENT The file specified by special or addr does not exist.

       ENOSYS The kernel has not been compiled with the CONFIG_QUOTA option.

       ENOTBLK
              special is not a block device.

       EPERM  The  caller  lacked  the  required  privilege  (CAP_SYS_ADMIN)  for  the  specified
              operation.

       ERANGE cmd is Q_SETQUOTA, but the specified limits are out of the  range  allowed  by  the
              quota format.

       ESRCH  No  disk quota is found for the indicated user.  Quotas have not been turned on for
              this filesystem.

       ESRCH  cmd is Q_QUOTAON, but the specified quota format was not found.

       ESRCH  cmd is Q_GETNEXTQUOTA or Q_XGETNEXTQUOTA, but there is no ID greater than or  equal
              to id that has an active quota.

NOTES

       Instead of <xfs/xqm.h> one can use <linux/dqblk_xfs.h>, taking into account that there are
       several naming discrepancies:

       ·  Quota enabling flags (of format XFS_QUOTA_[UGP]DQ_{ACCT,ENFD}) are  defined  without  a
          leading "X", as FS_QUOTA_[UGP]DQ_{ACCT,ENFD}.

       ·  The same is true for XFS_{USER,GROUP,PROJ}_QUOTA quota type flags, which are defined as
          FS_{USER,GROUP,PROJ}_QUOTA.

       ·  The  dqblk_xfs.h  header  file  defines  its  own   XQM_USRQUOTA,   XQM_GRPQUOTA,   and
          XQM_PRJQUOTA  constants for the available quota types, but their values are the same as
          for constants without the XQM_ prefix.

SEE ALSO

       quota(1), getrlimit(2), quotacheck(8), quotaon(8)

COLOPHON

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       project,  information  about  reporting  bugs, and the latest version of this page, can be
       found at https://www.kernel.org/doc/man-pages/.